Integrated circuit designers have always sought the ideal semiconductor memory: a device that is randomly accessible; can be written to or read from very quickly; is non-volatile, but indefinitely alterable; and consumes little power.
One common volatile memory is the DRAM in which information can be written to and read from as bits of data, e.g., a “1” or a “0,” where a “1” generally corresponds to one voltage state stored on a capacitor, and a “0” generally corresponds to another voltage state stored in the capacitor. The capacitor of the DRAM cell typically has an associated transistor that acts as a switch to allow the control circuitry on the memory chip to read from and write to the capacitor.
DRAM cells suffer from a number of shortcomings. First, the capacitor of a DRAM cell is extremely energy inefficient because capacitors of DRAM cells quickly lose their stored voltage, and need to be refreshed to prevent the cell from being discharged, resulting in high levels of energy consumption. Second, because DRAM cells are based on electrical signals, the speed of integrated chips are not only limited by the speed by which electrons travel through matter, but are also limited by the number of interconnections within the chip necessary to effect proper transfer and storage of the signals; these additional interconnections contribute to the problem of short circuits. Finally, the electrical signals used in conventional memory cells can interfere with each other, resulting in increased cross-talk, and decreased performance, which is undesirable.
Accordingly, there is a desire and need to construct a memory cell that improves upon the shortcomings of DRAM cells.